Shock absorber for vehicles



Jan. 1, 1929.

Pg. D. CHURCH SHOCK ABSORBER FOR VEHICLES 4 ,Mllullillrlllliili b, t

d s y 9, 9

CII

Patented Jan. l., lZ-

l ouin sierras "i" erin.

HAROLD D. CHURCH, OF FAIRFELD, CONNECTICUT, ASSIG-NOR OF ONE-TI-I'BD TOCHARLES MARCUS, OF NEW YORK, N. Y., AND ONE-THIRD TO RAYMOND P. LAN-SING, OF MONTCLAIR, NEW' JERSEY.

SHOCKABSOBJBER FOR VEHICLES. v

Application filed February 15, 1923, Serial No. 619,159. RenewedOctober12, .1925.

This invention relates to shock absorbers or vehicle spring checksespecially adapted for-motor vehicles.

The general object of the invention is'to y provide a friction shockabsorber which dispenses with any fluid media, is exceptionally strong,durable, compact, and is adapted for economical production..

An important object is to provide inappliyance of this class whichapplies 'a predetermined maximum force to retard relative movement ofthe vehicle body and axle in apredet-ermined direction, eitherconvergent or divergent, very quickly tter the commencement of suchmovement, and tomaintain the retardingl'force substantially consta-ntthroughout theremainder.ofthe stated movement, thus avoiding diicultiesencountered in'many types of retarders'in which'the retarding force isbuilt yup gradually and the maximum force is applied only after thevehicle partshave moved a considerable distance and acquired substantialmomentum.

A further object is to provide for applying a smaller but materialretarding torce to vehicle part movement in the direction op- Apositetothe direction in which the maximum retarding force is applied, as abovedescribed.

Another obj ect is to provide 'for an approximately or comparativelyfree oeriod, or slight range ot movement ofthe vehicle parts withoutconsiderable retarding eiiect within that range.

The invention involves the use of springs and co-operating inclinedsui-tacos, and an important object is to provide structures orarrangements of parts in which the frictional retarding eiiiect dependsmainly upon the spring pressure, the inclined or screw surfaces beingused principally or entirely to cimtrol the spring pressure. 'In onepreferred embodiment ot the invention l provide two springs, one ofwhich exerts a friction-producing` effect in both directions oishock-absorber movement, and the other exerts its maximumfriction-producing'eect in only one direction of movement and nofrictionproducing eiect in the other direction of movement.

An important purpose of the invention is to improve the structuralfeatures of devices of this class in various ways, with the objects ofmanufacturing 'ease and "economy and increased strength, durability,land 'improved operation of the appliance. @ne important eature is thesubstantialeiiclosure of thespring means within the inclinedlsurface orscrew and nut mechanism. "Other structural 'features are' suilicientlyreferredto hereafter.

The characteristicsland advantages of the "invention fare liurther!sufficiently explained in connection with the following detaildes-ription of the accompanying drawings,

which show one exemplifyingr embodiment oi' `shock absorber attached toa side frame member of a motor vehicle.

Figure 3 isa lsection at 3 3, Fig 2. Figure 4 is a detail view/,partlyin planand partly in section, ofthem'ain plate with its screw-sleeve,and the nut.

A `friction plate l, which )is the mainl'p'late or base of theappliance, isarr'ang'ed' to be securedto `a trame webl QOf a rmotor4vehicle lby bolts and nuts 3. "Gentrally locatedon' plate lis a sleevel of substantial diameter' and most desirably integral with the plate.The sleeve, which may be described 'as a screw-sleeve or hollow spindle,has an eX- ternal screw thread 5. ln one instance the pitch or leadangle of the 'thread is 15, but this angle may be varied-within properlimits for the .purposes in view. At its outer end sleeve 4 'has aninwardly projecting flange 6. A nut 7-is located vupon the screw-sleevein'engagement with screw thread 5. rllhe nut may be Vdeiined.infsomeinstances as a shifter since by a I'shifting movement'it throws a springinto and Vout of action as explained hereafter. At its'o'uter end thenut has an inwardlyiprojecting flange 9. The peripheryof the nutisprovidedwith a multiplicity of splines 10 cooperating with spline-Waysor channels inasleeve 11,"which to engage a screw thread 33 on sleeve11.

Y sleeve 28.

Vtion as the screw end may be neet.

is an operative part of and usually integral with a plate 12. Plate 12may be defined in some instances as a pressure member or pressure plate.

Between plates 1 and 12 is a movable friction plate 13 which has a leverarm 14 of suitable length provided with a ball-end fitting 15. Plate 13is apertured to accommodate screw-sleeve 4, and in the aperture issecured a bushing 16 which provides a bearing for the plate upon thesleeve adjacent to plate 1. Annular friction disks or rings 17 and 18 ofany suitable friction material are located between plates 1 and 13and/13 and 12 respectively, and most desirably these friction rings aresecured to plate 13 as by rivets 19 having heads located incounter-sinks in the disks. Y Filler rings 2O of cork or other suitablematerial may be placed about the peripheries of thev friction rings toexclude dirt, and the spaces between plates 1, 13 and 12 may beadditionally covered and the filler rings secured by a thin metal ring21 secured to plate 13 and having a slot at one side to accommodatelever arm 14.

Within the screw-sleeve 4 are located two yhelical springs 25 and 26, ofAwhich spring 26 is usually heavier than the other, that is to say, iscalculated to exert a greater end thrust, and this heavyy spring isusually located within the other. The inward ends of both springs restagainst an abutment or washer 27 having an internally threaded The outerend of spring 25 rests against fia-nge 6. The outward end of spring 26rests against a washer 30.. The peripheral margin of the washer restsagainst flange 9. A cap 31 ts over and encloses the outer end'of themechanism. This cap has a cylindrical flange 32 internally threaded Abolt 35 passes through a central aperture in the cap 31 and the threadedportion of the bolt engages in the threaded sleeve 28. The bolt may havea tapered shank portion 36 engaging a tapered socket 37 in capy 31, orit may be prevented from rotating by other means.

A retractable stop in the form of a screw 40 may be provided in cap 31,the inner end of this screw being arranged to engage between the splines10 of nut 7, or instead of this screw Varigid projection on the innerface ofthe cap in substantially the same loca- Then desired the innerend of the chamber within sleeve 4 containing the springs may be Vclosedor sealed in any suitable way, for example, by a flanged disk 45 forcedinto the inward end of the sleeve with a friction fit.

Figure 1 shows one application of the appliance to a motor vehicle. Theball end 15 of arm 14 is connected by a link 50 to any suitable fitting51 `secured to the vehicle axle 52. The app iance may be arranged toexert yrecoil.

the maximum retarding effect in either directien of relative movement ofthe vehicle frame and axle by reversing its position or by changing thelead of the threads of the screw sleeve and nut.

As shown, the appliance is arranged to apply the, greatest resistance tovehicle spring Supposing that the vehicle spring has been compressed byan upward movement of the axle in relation to the frame, at the end ofthat movement the parts will be in the position shown in Figure 2. Thereis a slight clearance between the outer portion of washer 30 and the endof sleeve 4, to allow for wear of the friction surfaces. The clearancebetween the washer and the sleeve end may be varied. by rotating the cap31 in relation to friction plate 12, and this may be done when stop 40is retractable by merely moving out the stop, or if the stop is fixed,the cap 31 may be turned by first backing out t le bolt 35 a suitabledistance and then moving plate 12 with its .sleeve 11 and cap 30outwardly slightly until the stop is free from the outer ends of splines10.

During the vehicle spring recoil lever arm 14 moves clockwise as viewedfrom'the outward end of the appliance, or away from the Vas isnecessaryr to take up clearance of the screw threads 5 and 8, or inother words, to bring the outward surfaces of the nut threads 8 incontact with the inward surfaces'of the sleeve threads 5. During thedescribed movement the nut is of course compelled to move along` withplate 12 by the spline connection between sleeve 11 and the nut. Thefrictional resistance to the described movement of course depends uponthe strength or thrust of spring 25 which may be varied greatly, and maybe in one specific instance about 2.50 pounds, more or less. In such acase the resistance to sliding during the described arm movement andwith an arm of a certain suitable length may be only approximately 22.5pounds at the end of the arm, or in other words, a 221/2 poundresistance to the initial spring recoil movement. This correspondsapproximately to an initial free period or angle of movement.

i.ihen the screw thread clearancehas been taken up arm 14 continues tocarry plate 12 along with it by frictional'contact, with slidingfriction only between friction ring 17 and plate 1 during another smallangle of movement, during `which thezangle of the right hand screwthreads 5 on sleeve 4 causes nut 7 to move inward or toward plate 1.Until this inward movement of nut 7 commences the Vthrust of spring 26is. entirely taken up between cap 31 which is in immediate Contact withnut flange 9 and washer 30 which is in immediate contact with theflange,and washer 27 which is connected to cap 31 by bolt 35; or in otherwords, the thrust of spring 26 is self-contained and eliminated as anoperative feature. lmmediately, however, that the described levermovement causes nut Y7 to be drawn inward, the outer end of the nutleaves contact with cap 81 and the thrust of spring E26 is appliedbetween the nut 7 through its liange .4) and washer 30, and washer 37,and so through bolt 35 and cap 31 to plate 12 vand through the frictiondisks and plate 13 to the surface of friction ring 17 which is slidingon plate 1. |lhe inner spring 26 may 'be and is usually made tohave aconsiderably greater thrust value than spring` 25. Thisthrust may be inone particular instance approxmately 900 pounds, more or less, andduring the described part of the recoil movement this pressure added tothe thrust of spring and exerted on a single sliding surface, mayIroduce a pull at the end of'arm 14 of approximately 119 pounds. Thisretarding effect exerted between the vehicle frame and axle takes intoconsideration the resistance of the splines 10 to the inward slidingmovement of the nut during` the described movement of arm 14. The splinefacesare under pressure and therefore exert an appreciable resistance tothe sliding,` movement, which may betaken into consideration in thecalculation of the angle of screw thread 5 and the pressures of one orboth springs.

t the end of the described small angle of movement further Vinwardinovement of the nut is prevented by contact of washer with the outerend of sleeve 4. Immediately thereupon, any rotative movement of the nutand of sleeve 11`with plate 12 is stopped and in the further movementofarm 14 sliding friction is provided at two points, that is, betweenplate 1. and friction ring' 17 and between plate 12 and friction ring;1S. This practically doubles the resistance to the vehicle springrebound applied throiugh link o0 at the end of arm 14, or in onespecilic instance, with springs and other factors as above, resistanceduring the ren'iaininp,` part of vehicle spring` recoil will heapproximately 3G pounds. A

In many cases, and especially' in all cases where the deiection of thevehicle spring has been so considerable as to make the checking of therecoil import-ant, t-he angle of movement of arm 14 after both springshave come in play to exert their full friction effect, and afterslipping commences between b'othof t-he friction rings'andtheadjacentplates, is

vby far t-he Y greater part of the-entire recoil vone point, are onlyAaA small part of the tot-al recoil movement. The lirst small angularmovement where thefriction resist-ance is'at a minimum, therefore,corresponds approximately t-o a free period or angle of movement duringlwhich the friction resistance is very moderate; in the next smallangularmovement the resistance becomes consid'erablefbut only approximatelyone-half of lthe maximum; and then practically instantly, and after onlya small partofthe total angular recoil movement of arm 14, the fullfriction resistance vis built up and maintained throughout the remainderof the recoil stroke. 'the result of this is that the movingl parts'ofthe vehicle do not khave time to gain-'greatmomentum force until thefull retarding effect is applied and the checking of the recoil actionistherefore very effective with reasonable `frictional resistance,whereas, as in other types of retarders, Awhen the n'iovingparts of thevehicle such as the axle structure and the body are'permitted to reach afairly rapid rate of movement before the principal retarding 'force isapplied,the momentum effect is correspondingly increased and the forcethat mustthen be applied to check-the movement is increased in aneven'greater ratio.

lVhenthe road wheel of the yvehicle encounters an obstacle tending'tomove the axle upward in relation tothe frame, arm 14 movescounter-clockwise or toward theobserver in Fig. 2. In the first part ofthis movement, if it occurs `immediately-alfvter a recoil movement whichcausesithenut to be moved inward 'until stopped by Contact of washer 30with the end of sleeve 4, as above explained, the nut is unscrewednorIrotated counter-clockwise until its outer endcomes Vin contact with cap31, byreason of the frictional engagement between plate 12 andlfrictionring,` 18 which causes plate `12 andthe nut to move along with arm 14.During this angle of movement sliding friction occurs only betweenfriction ring 17 and plate 1. rlhe resistance of the splines 10 tooutward movement of the nut during the described arm movement tends toreduce the pressure on the friction disks. The pull at the end of arm 14during the described movement due to the thrust of the two springsandthe spline resistance, is'fairly moderate, somewhat less in aparticular instance than friction resistance during the second smallangular movement of recoil as above described, or in other words, in aspecific'case vabout 87.5 pounds,

more or less. As soon as the nut comes in contact with cap 3l the thrustof spring 526 is again self-contained and negligible during the furthermovement of arm 14 in the `de-v scribed direction.

Resist-ance to further compression of the vehicle spring is thereforethat due to the thrust of spring 25 exerted upon two sliding surfaces,that is, the surfaces of both friction rings 17 and 18 in contact withthe respective plates l and l2, since sliding commences between plate 12and the adjacent friction ring` as soon as outward movement of the nutstops. The thrust effect of the spring is, however, during the remainingpart of the arm movement reduced by the angularity of the screw thread5, since plate l2 with its sleeve engaging nut 7 through the splines,tends to rotate the nut backward and tluias to reduce the effectivespring thrust, so that the frictional force tendingT to check the'vehicle spring compression during the great part of the compressionstroke may be very small, the force applied at the end of arm i4 beingin a particular example about 2O pounds, more or less.

The spring pressure and pull values state( are of course only oneexample, are given mainly for ready comparison of the forces applied tothe movable friction plate and lever arm under the various operativeconditions. The spring vpressures and resultant forces may be variedwithin wide limits, with respect to the different classes and weights iof vehicles, and the amount of retardation desired.

From the above description it will be evident that the maximum pull atthe end of arm 14 is a function of the two spring pressures plus theresistance of the splines l0 to sliding, and that the latter is only asmall percentage of the total pressures involved. .ln the particularexample above mentioned, a variation of 100% vin the co-efficient offriction of the splined surfaces onlyvaries the maximum pull on arm Msix per cent.y The operation of the appliance therefore is veryconsistent in spite of more-or-less variations in the linish of thespline surfaces.

The pitch of the screi sumciently ne so that irrespective of efficientof friction on the screw surf there .is at all times an er( ss of wineup power due to the thrust effect sur' 25, and the friction effect sothat varia in the screw thread co-e "Jion thread 5 is made the l iii cien t oi have no apl'neciffiblc bearing ou tt? pull es erted at the endof arm it. The angle the screw th read is always made steeper than theangle of repose of the ma rial used, in

order to eliminate any possibility of the nut 7 jamming' against theendof sleeve i and failing to unscrew.

The appliance is designed to operate with r with-out lubrication, andthe fashers sur- Leen/iis roundingthe friction rings and the` coveringof the inner end of sleeve 5 prevent the entrance of water and dirt.

I claim: l

l. A vehicle spring controlling` appliance comprising relatively movablefriction members, a spring normally inactive, and means controlled by arelative movement of the members and adapted to establish an activecooperation between the spring and the friction members to therebyapplyv pressure to their frictional contact, said controlling ieansincluding` a shifter having a rotary and longitudinal movement andactuated by one of said friction members and adapted when movedlongitudinally to establish such active cooperation between the spring'and the friction members.

Q. A vehicle spring controlling appliance,

rs, a spring` for producing frictional er act of the members, meansnormally maintainin the spring in effective condition, and meanscontrolled by a relative movement of the members to malte the springactive for the purpose stated or to render it ineffective for thatpurpose.

A vehicle spring controlling appliance, comprising relatively movablefriction members, a shifter, inclined surfaces effective between theshifter and one of said members to move the shifter upon movement ofsaid'member, a spring in opposed relation to the shifter, and a springabutment, the parts being arranged so that when the shifter is moved in.one direction, the spring is effective to provide friction pressurebetween said members and when the shifter moves in the other directionthe spring thrust is taken up between the abutment and a fixed part ofthe appliance and is ineffective to produce friction pressure,

a. A vehicle shock absorber or spring retarder comprising a frictionmember, a shifter mounted for relative movement on said member, a secondfriction member arranged for oscillation and co-operating with saidshifter and adapted, when rotated, to move the shifter longitudinally, athird fric- 'tion member arranged for rotative movement between thefirstand second. friction members, and a if ,y pressure means adapted toc-ert vicini p pr ssure against the shifter when so movedlmugitudinally.

vehicle. .shoe-lr absorber or spring' retarder comprisinga frictionmember, a shifter mountel for, relative movement on said member, asecond friction member arranged for oscillation and cri-operating withsaid shifter and adapted, vwhen rot-ated, to move the shifterlongitudinally, a third friction member arranged for rotative movementbetween the first and second friction members, a yielding pressure meansadapted to exert yielding pressure against the shifter orisingrelatively oscilla-table .friction CFI when so moved longitudinally, anda yieldable controlling means acting on a friction member.

6. A vehicle shock absorber or spring retarder comprising a frictionmember, a spindle member thereon, a shifter mounted for movement on thespindle member, a second friction member mounted for rotation andco-operating with said shifter and adapted, when rotated, to move theshifter longitudinally, al third friction member arranged for rotativemovement between the first and second friction members, a springabutment, a pressure spring bearing against said abutment, meansnormally taking up spring pressure without substantial effect upon thefriction members and means acting upon relativev movement of certain ofthe friction members to render the spring active and apply its pressureto the friction members. 1 v

7. A vehicle shock absorber or spring retarder comprising a frictionmember, a spindle member thereon, a shifter mounted for movement on thespindle member, a second friction member mounted for partial rotationand co-operating with said shifter and adapted, when rotated, to movethe shifter longitudinally, a third friction member arranged forrotative movement between the first and second friction members, ayielding pressure means adapted to exei't yielding pressure against theshifter when so moved longitudinally, and a contiolling yielding meansacting on said second friction member.

8. A shock absorber or spring retarder for vehicles comprising a mainfriction plate, a'

spindle thereon, a shifter having screw thread engagement with thespindle, a second frictionV plate arranged for rotative movement andhaving splined connection lwith the shifter, a third friction platearranged between and'having frictional engagement with the rst andsecond plates, and a. pressure spring adapted to resist longitudinalmovement of the shifter.

9. A vehicle spring controlling appliance, comprising relatively movablefriction members, vyieldable means for exerting pressure upon saidmembers, and means including inclined elements controlled by movement ofone of the friction members for causing said yieldable means to exert afriction effect in one direction of movement, and for eliminating thefriction effect of the spring in the other direction of movement.

l0. A vehicle spring controller comprising relatively revoluble mainfriction members adapted to be connected to two vehicle parts such asthe frame and axle, a shifter adapted for axial movement, a revolublepressuire member frictionally oprated by one of 4said main frictionmembers, means including an` inclined element for moving the shifteraxially upon rotative movement of the pressure member, yieldablepressure means for applying friction pressure to the friction surfacesthrough the pressurelm'einber upon substantially rotary` movement ofthepressure member in-'one direction, and means for taking up thepressureefi'ect ofsaidpressure means to render sa'id'means inactive toproduce friction pressure when the pressure member moves substantiallyinthe other direction.

` 1l. Avehicle spring controller comprising relatively revoluble' main'friction members adaptedto be connected to two parts of a vehicle-suchas the frame and axle, a pressure member'frictionallyope 'ated by-one ofsaid main friction members, a revoluble and axially'movable shifterconnected to rotate with the pressure member, means including'aninclinedelement for vmoving Vthe shifter axially when it is rotated,yieldablepressure means for applying pressure to the frictionsurfacesthrough'the pressure member whenthe latterv rotates in vone direction,means normally taking up the pressure effect of said pressure meanswithout creating pressure onA the friction'surfaces, and meansffoi"locking thek shifter against furtherrotation after/'it'l has rotated asubstantial distance with the 'pressure member in the direction whichstresses the pressure means to'applypressure to the friction surfaces.

l2. A vehicle springfcontrollmg appliance comprising "relativelykmovable friction members, a springVcoiistantly .exerting pressure" uponsaitlm'embers, another springaiidrmeans controlledby movement of one ofthe friction niei'nbers for causing said, other spring to exert'a fri y`ony eifect'in one direction of movement v vand for eliminating thefriction eect ofthe spring yin the other direction of movement'.

13." i A 'vehicle spring controlling appliance comprisingrelativelyzmovable friction meiril' bers, a spring' constantly. exerting pressureupon said ii'iember's, another spring andmea'ns including inclined'elements controlledf'by ly urge said members Yinto frictional engage`ment, another spring and means controlled by'movement of one ofthefriction members serving to eliminate the effect" of said other springin one direction of movement and to' cause application of the effect ofsaid other` spring in the other direction of movement.

l5. A vehicle spring controlling mechanism comprising two relativelyrotatable friction members, a spring arranged to constantly urge saidmembers into frictional lengagement, another spring and meansv includingfixedV and' relatively movable inclined mem'- bers controlled bymovement of one of the friction members serving to eliminate the effectof said other spring in one direction of movement and to causeapplication of the effect of said other spring in the other direction ofmovement.

16. An appliance of the class described comprising a main plate, apressure plate, a third plate arranged to oscillate between the mainplate and the pressure plate, a spring arranged to constantly exertpressure tending to urge the plates to frictional contact, springabutments, a second spring normally exerting a self-contained pressurebetween the abutiiients, and means actuated by rotary movement of thepressure plate in one direction for moving one lof thespring abutmentsand causing the spring pressure to be applied to urge the plates tofrictional engagement.

17. An appliance of the class described comprising a first frictionplate, a pressure plate, a third plate arranged to oscillate betweenvthe main plate and the pressure plate, a spring arranged to constantlyexert pressure urging the plates to frictional contact, a second springnormally exerting a self-contained pressure, and means includinginclined surfaces actuated by rotary movement of the pressure plate inonly one direction for causing the spring pressure to be applied to urgethe plates to frictional engagement.

18. A vehicle spring controlling appliance comprising a main platehaving a spindle provided with a screw thread, a nut engaging the screwthread, a pressure plate having slidable engagement with the nut, arelatively rotatable friction plate between the main plate and thepressure plate, a spring constantly acting between the main plate andthe pressure plate tending to urge them together, another spring,abutments between which said other spring normally exerts aself-contained thrust, and means actuated by the nut for causing thethrust of said other spring Vto be applied to urge the plates together.

19. A vehicle spring controlling appliance comprising a main platehaving a sleeve pro` vided with an external screw thread, a nut engagingthe sciew thread, a pressure plate having splined engagement with thenut, a relatively rotatable friction plate between the main plate andthe pressure plate, a spring constantly tending to urge the main plateandv the. pressure plate together, another spring, abutments betweenwhich said other spring normally exerts a self-contained thrust, andmeans actuated by the nut in only one direction of friction platemovement for causing the thrust of said other spring to be appliedtourge the plates together.

20. A shock absoi'ber or spring retarder for vehicles comprising a mainfriction plate, a pressure plate, a friction plate oscillatably mountedbetween the main plate and pressure plate, a movable member having anVinclined surface cooperating with an inclined surface ated by movementof said movable member when frictionally impelled by the pressure plateto take up the thrust of said spring without operative effect in onedirection of movement and to apply the thrust of the spring to squeezethe friction plate between the main and pressure plates in the otherdirection of movement.

21. A shochabsorber or spring retarder for vehicles con'iprising a mainfriction plate, a pressure plate, a friction plate oscillatably mountedbetween the main plate and pressure plate, a movable member havinganinclined surfare coolrierating with an inclined surface in fixedrelation to the main plate, said meinbcr alsojhaving a movableconnection with the pressure plate, a spring, and means actuated bymovement of said movable member when frictionally impelled by thepressure plate to ialre up the thrust of said spring without operativeeffect in one direction of movement and to apply the thrust of thespring to squeeze the friction plate between the main and pressureplates in the other direction of movement, and another spring arrangedto exert pressure constantly tending to apply friction to said frictionplate.

22. A shock absorber or spring retarder for vehicles comprising a mainfriction plate, a pressure plate, a friction plate oscillatably mountedbetween the main plate and pressure plate, annular friction ringssecured to opposite surfaces of said friction plate, a movable memberhaving a screw thread cooperating with a screw thread in fixed relationto the main plate, said member also having a spline connection with thepressure plate, a thrust-spring, 4and means actuated by movement of saidmovable member when frictionally impelled by vthe pressure plate to takeup the thrust of said spring without effect upon the plates inl onedirection of movement and to apply the thrust of the spring to squeezethe friction plate between the main and pressure plates in the otherdirection of n'iovement.

23. A shock absorber or spring retarder for vehicles comprising a mainfriction plate, a pressure plate, a friction plate oseillatably Vmountedbetween the main plate and pressure plate, annular friction ringssecured to opposite surfaces of said friction plate, a movable memberhaving a screw thread cooperating with a screw thread in fixed relationto the main plate, said Vmember also having a spline connection with thepressure plate, a thrust-spring, and means actuated by movement of saidmovable member when frictionally iinpelled by the pressure plate to takeup the thrust of said spring without effect upon the plates in onedirection of movementV and to apply the thrust of the spring to squeezethe friction plate between the main and pres- `sure plates in the otherdirection of movement,vand another spring arranged to exert pressureconstantly tending to apply friction to said friction plate.

24. In an appliance of the class described, a base plate, a hollowspindle integral therewith and having an external thread, a nutrevolving on the spindle in engagement with its thread, a friction platearranged for axial movement and secured against rotative movementrelative to the nut, a friction plate oscillatabl)V mounted about thespindle between the main and pressure plates, a spring abutment withinthe spindle and connection 'therefrom to the pressure plate, a spring`constantly acting between the spring abutment and a member of theSpindle, another spring acting against the spring abutment and arrangedto exert pressure against the nut, both of the springs being housedsubstantially within the spindle.

25. In an appliance of the class described, a base plate, a hollowspindle integral therewith and having an external thread, a nutrevolving on the spindle in engagen'ient with its thread, a frictionplate arranged for axial movement and secured against rotative movementrelative to the nut, a friction plate o'scillatably mounted about thespindle between the main and pressure plates, a spring abutment withinthe spindle and an adjustable conneetio-n therefrom to the pressureplate, a spring constantly acting between the spring abutment and amember of the spindle, another spring acting against the spring abutmentand arranged to exert pressure against the nut, both of the springsbeing housed substantially within the spindle, movement of the nutbeing' checked in one direction by contact with a member connected tothe pressure pla-te and in the other direction by engagement with thespindle with a certain range of free movement between the twoposit-ions.

26. A vehicle spring controlling appliance comprising' a main plate.having a central sleeve member provided with an external screw threadand also having an inwardly projecting flange, a nut engaging the screwthread and having' an inwardly projecting flange located above thesleeve flange, a pressure plate having splined engagement with the nut,a friction plat-e arranged for oscillation about the sleeve between themain plate and the pressure plate, a spring abutment within said sleeve,a spring bearing at one end against said abutment and at the other endagainst said sleeve flange,.another spring bearing at one end againstsaidabutment and arranged to exert its pressure against the nut, andmeans connecting said spring abutment to said pressure plate so that thethrust of the first named spring is constantly exerted t0 urge the mainand pressure plates convergently, and the thrust of the second namedspring is self-contained and ineffective in one direction of movement ofth-e friction plate and is exerted to urgey the main plate and pressureplate convergently in the other direction of movement of the frictionplate.

27'. A vehicle spring controlling appliance comprising a main platehaving a central integral sleeve member provided with an external screwthread and also having' an inwardly projecting flange, a nut engagingthe screw thread and having an inwardly projecting flange located abovethe sleeve flange, a washer engaging said nut flange, a pressure platehaving splined engagement with the nut, a friction plate arranged :foroscillation about the sleeveA between the main plate and the pressureplate, ay spring abutment within said sleeve, a spring bearing at oneend against said abutment and at the other end against said sleeveflange, another spring bearing at one end against said abutment and atthe other against said washer, a cap member connected to said pressureplate and a connection between said cap member and said spring abutment,the parts construct-ed and arranged so that the thrust of the firstnamed spring is constantly exerted to urge the main and pressure platesconvergently and the thrust of the second` named spring isself-contained and ineffective in one.v direction of movement of thefriction plate and is exert-ed to urge the main plate and pressure plateconvergentlyin the other direction of movement of the friction plate.

28.l In a shock absorber or spring check for vehicles, a i'irst frictionplate, a second relatively oscillatable friction plate, a pressuremember arranged to cause application of retarding friction to the secondplate, a first spring constantly exerting thrust tending to urge thepressure member to friction al engagement, a second thrust spring,abutments therefor, and an inclined actuating member in non-rotativerelation to the first plate and cooperating with t-he pressure memberandv one of the spring abutments so that the pressure member is actuatedby frictional engagement with the second plate when the latter is movedin either direction from any operative position, and both springs andthe inclined member cooperate to apply a maximum frictional retardingeffect to the second plate in one direction of movement, and the thrustof the second spring is taken up by the abutments withoutpressure-effect on the pressure member and the first spring exerts areduced retarding effect, in the other direction of movement.

Signed at New York in the county of New York and State of New York this31st day of January A. D. 1923.

AROLD D. CHURCH.

